This invention relates generally to surgically implantable valves, and more particularly, to one-way flow control valves for controlling the flow of cerebrospinal fluid out of a brain ventricle and preventing backflow of fluid into the brain ventricle.
As is well known in the medical arts, to relieve undesirable accumulation of fluids, it is frequently necessary to provide a means for draining a fluid from one part of the human body to another in a controlled manner. This is required, for example, in the treatment of hydrocephalus, an ailment usually afflicting infants or children in which fluids which ought to drain away accumulate within the skull and thereby exert extreme pressure and skull deforming forces.
In treating hydrocephalus, cerebrospinal fluid accumulated in the brain ventricles is drained away by a catheter inserted into the ventricle through the skull, and the catheter is connected to a tube which conducts the fluid away from the brain to be reintroduced into the vascular system, as by extending through the patient's jugular vein to the atrium portion of the heart. To control the flow of cerebrospinal fluid and maintain the proper pressure in the brain ventricle, a pump or valve is placed in the conduit between the brain and the heart atrium.
Many such devices have been used heretofore, but prior devices have tended to become obstructed by particulate matter entering the drainage system or by the backward diffusion of blood into the system. Further, some prior devices have included moving parts which tended to adhere to other parts of the device and become immobile. When this occurs, the device itself becomes a barrier in the drainage system, and it adds to the problem it is intended to solve.
Moreover, manufacturers have been faced with a dilemma regarding the use of metal components in such valves. Some prior devices have included metal components which tended to interfere with X-ray photography and produce radiation scatter ("sunburst effect") on films taken by computerized axial tomography (CAT) scanning equipment, and such X-ray photography and CAT scanning frequently accompanies the use of surgically implanted flow control valves. However, it is desirable in some instances to be able to ascertain specific information from an implanted device by X-ray photography without having to reopen the patient's skin. For instance, it would be very desirable to provide X-ray detectable means for designating the proximal-to-distal flow path of the implanted device. Additionally, an X-ray detectable marker which would facilitate detection of a separation of drainage tubing from the valve could be very useful to an attending physician where doubt exists as to the integrity of an implanted shunt system.
Accordingly, there has been a long existing need in the medical arts for a convenient and effective device for controlling the flow of fluid from one part of the human body to another, which device is relatively inexpensive to manufacture and which can be constructed substantially of non-metallic parts which are not subject to adhering to one another and causing malfunction of the device. Such a device would preferably include proximal-to-distal flow indicators as well as markers facilitating the detection of a drainage tubing disconnect, such markers and indicators being detectable by X-ray photography. As will become apparent from the following description, the present invention satisfies these needs and provides other related advantages.